SCR-270

Radar History, The U.S. Army SCR-270 radar, "The Pearl Harbor Radar"

In April of 1937 a LtC. Davis an officer in an Army Air Corps Putsuit Squadron in the Panama Canal Zone (CZ)sent a request for a "Means of Radio Detection of Aircraft" direct to the U.S. Armys Chief Signal Officer (CSig.), bypassing normal channels of command. This indicated to me that LtC. Davis must have been coached by BG H."Hap" Arnold then the assistant Chief of the Air Corps in the Army. (The U.S. Air Force [USAF]started out as a branch of the Signal Corps before WW-1 and was made an independent service in 1947 after being through several phases such as "The Army Air Service, Army Air Corps, Army Air Forces, etc.)

The Signal Corps had been working on an early type of VHF radar equipment @ Fort Monmouth, NJ for the Coast Artillery (That was to become the SCR-268 Searchlight radar.) & was about to have a demo @ Ft. Monmouth in May. After the succesful SigC demo @ Ft. Monmouth, BG Hap Arnold wrote to the CSig requesting a "Mobile Detector Set" for the Air Corps on June 3rd, 1937.

The Signal Corps Labs had been ordered to move its secret radar work to the neck of Sandy Hook, NJ @ Fort Sandy Hook the coast artillery defense site for lower New York harbor and work was immediately begun on the Air Corps request for what was to become known (In 1940)as the "Radio Set SCR-270" the USAF's very first radar set. Parts of the embryo SCR-268 were diverted to this new customers project, delaying the compleation of the SCR-268.

A contract was let to Westinghouse for the vital 106 MHz transmittting tube the WL-503/VT-122 in October and by January of 1939 a pair of these state of the art water cooled tubes were putting out 100 kW of peak power & were incorporated into the first SCR-270 that were used in the Army's manuevers that summer. Later model '270's used an RA-60 HV-Rect. that incorporated a WL-531/VT-141 rectifier tube. Couse of Newark, NJ built the antenna mounts & its K-23 & later K-64-A trailers, that were derived from well drilling rigs. Fred M. Link of NYC had a $100.00 per week SigC contract to supply BC-438 & BC-439 Frequency Meters & BC-423 "Tweeter" Signal Source units, later production was by "TEMPLETONE". The Terpenning labs built the first RA-33 High Voltage Rectifier Units, RCA built the BC-403 receivers that used a "State of The Art" 1630/VT-128 2nd RF-Amp. tube and the BC-404 Oscilloscopes with a stock television 5BP4 CRT as sub-contractor to the Westinghoue Electric Company of Baltimore, MD that built the 1800 odd SCR-270/1's from 1940-44. Later model '270's were equipped with a 12' PPI & A scopes borrowed from the SCR-527 of British design & built in the U.S. by General Electric. RCA did some later antenna design work also.

A fixed version of the '270, SCR-271-A, s/n 1 was delivered to the CZ and "Went to Radiate" (in operation) by October of 1940 @ Ft. Sherman on the East end of the Panama Canal. It picked up airliners @ 117 miles away in its intial test run. The second set was set up on "TOBAGA" Island on the West end of the Canal by December of 1940 thus succesfuly giving Radar coverage to the vitally important but vunurable Panama Canal.

The SCR-270-D model was brought out of retirement in the fall of 1950 and was found to be quite useful in locating those new-fangled "Sealth" fighter aircraft of the time the USAF P-80 & the Soviet MIG-15, that the newer Microwave radar's had trouble "painting." The Chinese have a radar design based on the SCR-270 in use today & will sell you one...

SCR-270-B s/n 012 was at Opana Point on the morning of The Seventh of December, 1941 manned by two U.S. Army Privates. At 0700 hours the set was supposed to be shut-down but the guys decided to get some more OJT time in since the "Chow Truck" was late.

Just after 0700 Elliot & Lockard saw the Jap armada of aircraft approaching Ohau and tried to warn higher HQ with no luck and Pearl Harbor got hit at 0800.

Look up "SCR-270" on the web for more info. Don Helgeson, G&S

[Category:Radar]]